I predict the entry level PC market will not disappear, and the memory strain will go away in a few years.

Now, does that mean you will be able to buy a laptop with 512GB SSD, decent battery life, and 32G RAM for under $500? No, "entry level PC" hasn't historically meant that. In 2016, an entry level laptop was a Dell Inspiron that had 2GB RAM and 64 GB flash storage. The RAM was DDR3 and the screen resolution was a "vibrant" 1366x768. It cost about $250, which today is about $340.

Checking online, a cheap laptop is the Acer Inspire on Amazon for $340 available today, it has 8GB DDR5 RAM and 128GB SSD NVMe. With a 15 inch HD screen, built in wifi. It's a much more capable machine for less, adjusting for inflation, than the Inspiron 11. This in the middle of a RAM crisis.

I just bought a refurbed Dell Rugged 14 Pro with 32G RAM and a dedicated ADA 500 and felt like it was light on the RAM side, and then I had stop myself and remind myself that perhaps I should focus a bit more on efficiency, because there is no amount of technological innovation that can outpace software bloat and inefficiency. Running Linux helps keep the RAM needs reasonable. But the efficiency GPU in my laptop has twice as much onboard RAM than the entry level laptop 10 years ago.

This jumps out for me:

    ... concerns about security vulnerabilities on aging hardware ...

That's the cost of shoddy engineering. A security fix is basically a recall in any other branch of industry. We've gotten so good at recalls that we can basically throw anything at the wall and fix it next month if foobar again. And now the party is, well, far from over, but at least cooling down a bit.

There is no reason for PC hardware from 10 or even 15 years ago to not be usable today, except shoddy engineering and software decision makers giving up. I own a thinkpad x220 so I can mean that.

End of 20's new factories come online that will massively reduce RAM price. No level of PCs will go away.